• Transactions of the Korean hydrogen and new energy society
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• v.15 no.2
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• pp.108-118
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• 2004

To find out rational design and synthetic strategies toward efficient hydrogen storage materials, molecular modeling and quantum mechanical studies have been carried out on the MOFs(Metal-Organic Frameworks) having various organic linkers and nanocube frameworks. The calculation results about the free volume ratio, surface area, and electron density variation of the frameworks indicated that the capacity of the hydrogen storage of MOFs was largely dependent on the specific surface area and electron localization around benzene ring rather than the free volume of MOFs. The prediction of the modeling study could be supported by the hydrogen adsorption experiments using IRMOF-1 and -3, which showed more enhanced hydrogen storage capacities of IRMOF-3 compared with the IRMOF-1's at both experimental conditions, 77K, ∠ $H_2$ 1 atm and ambient temperature, ∠ $H_2$ 35 atm.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.2
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• pp.151-160
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• 2014

CL-SPEEK/Cs-TPA/$CeO_2$ composite membrane was prepared for polymer electrolyte membrane water electrolysis (PEMWE). In order to improve the electrochemical, mechanical, durabilities and electrocatalytic characteristics, engineering plastic of polyether ether ketone (PEEK) as polymer matrix was sulfonated and the organic-inorganic blend composite membranes was prepared by loading cesium-substituted tungstophosphoric acid (Cs-TPA) by titration method with cross-linking agent contents of 0.01mL. Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the PEMWE circumstance and to increase the duration of the membrane. CL-SPEEK/$Cs_{(1)}$-TPA/CeriaIn conclusion, 1% membrane showed the optimum results such as 0.119 S/cm at $80^{\circ}C$ of proton conductivity and 62MPa of tensile strength.

• Information Systems Review
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• v.17 no.1
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• pp.171-197
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• 2015

SNS provider's biggest interest lies in enhancing user satisfaction through user request analysis and developing services to induce continuous use of those devices. In particular, setting up management directions to develop SNS at maturity is important and it is also important to identify the functions which SNS users are pursuing for and identify what's considered unsatisfiable among the services currently provided in light of user expectations. To this end, this study further presents sociality quality and personal emotional quality reflecting the characteristics of SNS to the existing quality factors and expands to Expected Confirmation Model. This study further took into account of sociality quality and personal emotional quality reflecting the characteristics of SNS and approached to them from the perspective of quality in a comprehensive way, analyzed the degree of impact on recognition factors, and presented the factors that had an impact on the satisfaction with usage and intention to use continuously.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.4
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• pp.475-480
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• 2010

The thermal barrier coating of a gas turbine blade was degraded by isothermal heating in a furnace and by varying the exposure time and temperature. Then, a micro-Vickers hardness test was conducted on the cross section of the bond coat and Ni-based superalloy substrate. Further, the thickness of TGO(Thermally Grown Oxide) was measured by using an image analyzer, and the changes in the microstructure and element contents in the coating were analyzed by using an optical microscope and by performing SEM-EDX analysis. No significant change was observed in the Vickers hardness of the bond coat when the coated specimen was degraded at a high temperature; delamination was observed between the top coat and the bond coat when the coating was degraded for 50 h at a temperature $1,151^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.199-206
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• 1982

Histological changes occurred by freezing storage and subsequent thawing, and changes of muscle fiber after heating and drying of the eel (Anguilla japonica) were observed under microscope . The results are as follows : (1) After one month of freezing storage the muscular tissue produced considerable number of extracellular and intracellular ice crystals. The sample stored at the temperature of $-40^{\circ}C$ produced ice crystals inside the muscle cells while sample stored at $-20^{\circ}C$, outside. (2) No changes were observed in the hypodermic fat after thawing regardless of storage temperature, while insufficient recovering of muscle cells were detected in the muscular tissue. Muscular tissues which have been stored $-20^{\circ}C$ showed severe change in shape due to dehydration. (3) Microscopic observation on muscle homogenate showed loss of transparency due to free-zing, disfiguration and contraction by drying and water seperation, and elasticity by heating.

• The Journal of Korean Medicine
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• v.22 no.4
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• pp.69-78
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• 2001

Objectives : It is known that cigarette smoking is associated with increased risk of both thrombotic and hemorrhagic stroke. However, in Korea, especially in the academic world of Korean Medicine, there is a lack of study about the relation between cigarette smoking and stroke. We carried out a case-control study to clarify the relation between cigarette smoking and stroke. Method : We interviewed 441 stroke patients (236 men, 205 women) as a case group and 432 non-stroke patients (208 men, 224 women) as a control group. We investigated the smoking pattern of all patients and stroke-subtype of the case group. Smoking pattern is classed into two (Class I), four (Class II) and five groups (Class III). Class I consists of current non-smokers and current smokers. Class II consists of non-smokers, former smokers, current light smokers and current heavy smokers. Class III consists of never smoked, secondhand smokers, former smokers, Current light smokers and current heavy smokers. Stroke-subtype consists of cerebral infarction and cerebral hemorrhage. Results : The percentage of current smokers of case group is higher significantly than that of control group. The number of cigarettes smoked per day is associated positively with the risk of stroke. According to our study, generally cigarette smoking is related with ischemic stroke. The percentage of secondhand smokers of the case group is lower than that of the control group. According to our study, characteristically secondhand smoking is associated with hemorrhagic stroke. Conclusions : From the above results we found that cigarette smoking is an important risk factor of stroke - especially cerebral infarction - and the number of cigarettes smoked per day is associated positively with the risk of stroke. Characteristically according to our study, secondhand smoking is associated with hemorrhagic stroke. Overall we conclude that cigarette smoking may be an important preventable factor for stroke.

• ALGAE
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• v.23 no.3
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• pp.231-240
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• 2008

The species composition and variation of benthic marine algae at Daejin and Jukbyeon on the mid-east coast of Korea were investigated seasonally from August 2006 to April 2007. As a result, the total of 85 species, including 8 chlorophytes, 26 phaeophytes, 50 rhodophytes and 1 sea grass were identified. 52 species were found at Daejin and 74 species at Jukbyeon. Dominant species in importance value were Corallina pilulifera, Chondrus ocellatus, melobesioidean algae, Sargassum horneri, Sargassum yezoense and Phyllospadix japonica at Daejin, and Corallina pilulifera, melobesioidean algae, Phyllospadix japonica, Acrosorium polyneurum, Sargassum siliquastrum and Hizikia fusiformis at Jukbyeon, respectively. The vertical distribution of algae were characterized by Corallina pilulifera, Hizikia fusiformis, Sargassum spp. (S. siliquastrum, S. yezoense) and Symphyocladia latiuscula at intertidal zone, Sargassum spp. (S. horneri, S. serratifolium, S. yezoense), melobesioidean algae, Phyllospadix japonica and Corallina pilulifera at 1 m depth, melobesioidean algae, Phyllospadix japonica and Sargassum spp. (S. horneri, S. yezoense) at 5 m depth and melobesioidean algae, Phyllospadix japonica and Sargassum spp. (S. horneri, S. micracanthum, S. yezoense) at 10 m depth.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.3
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• pp.399-405
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• 1996

The effects of stearic(18 : 0, SA), oleic(18 : 1 cis, OA) and elaidic acid(18 : 1 trans, EA) on the cell growth, contents of cellular lipids, and the fatty acid composition of cellular and medium lipids in Hep-G$_2$cells were evaluated. The cells were incubated in serum-free medium containing 25, 50, 100 and 200$\mu$M of a fatty acid combined with albumin for 2 days. The fatty acid concentration up to 100$\mu$M showed the normal growth, but the cell growth decreased in the presence of 200$\mu$M fatty acid. The treatment of cells with 100$\mu$M of a fatty acid for two days significantly(p<0.05) increased the cellular triglyceride(TG) content in all fatty acid groups compared to control, but TG contents was not significantly different among all treatment group, but total cholesterol(TC) was the highest level in EA group. The level of free cholesterol(FC) and cholesteryl ester(CE) was similar to those of TC in all fatty acid treated group. The cellular phospholipid(PL) contents were similar between the control and all fatty acid groups. The treatment of cells with SA has no notable effects on the fatty acid composition of TG, CE and PL. The OA treatment caused significant increases in CE(51.2%) and PL(29.8%), but not in TG. The EA treatment resulted in 10.1, 10.7 and 7.8% of $C_{18:1\;trans}$ content in cellular TG, CE, and PL. The TG, CE and PL of medium were relatively similar between SA and OA groups. In EA treated group, TG, CE and PL of medium contained 17.0%, 0.7% and 5.6% of $C_{18:1\;trans}$, respectively.

• Phonetics and Speech Sciences
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• v.8 no.2
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• pp.31-39
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• 2016

In emergency dispatching at 119 Command & Dispatch Center, some inconsistencies between the 'standard emergency aid system' and 'dispatch protocol,' which are both mandatory to follow, cause inefficiency in the dispatcher's performance. If an emergency dispatch system uses automatic speech recognition (ASR) to process the dispatcher's protocol speech during the case registration, it instantly extracts and provides the required information specified in the 'standard emergency aid system,' making the rescue command more efficient. For this purpose, we have developed a Korean large vocabulary continuous speech recognition system for 400,000 words to be used for the emergency dispatch system. The 400,000 words include vocabulary from news, SNS, blogs and emergency rescue domains. Acoustic model is constructed by using 1,300 hours of telephone call (8 kHz) speech, whereas language model is constructed by using 13 GB text corpus. From the transcribed corpus of 6,600 real telephone calls, call logs with emergency rescue command class and identified major symptom are extracted in connection with the rescue activity log and National Emergency Department Information System (NEDIS). ASR is applied to emergency dispatcher's repetition utterances about the patient information. Based on the Levenshtein distance between the ASR result and the template information, the emergency patient information is extracted. Experimental results show that 9.15% Word Error Rate of the speech recognition performance and 95.8% of emergency response detection performance are obtained for the emergency dispatch system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.70-75
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• 2006

The performance of a turbopump system composed of an inducer, an impeller, a volute and seals has been computationally analyzed. To save the computational time, only one flow passage of the inducer and impeller is considered for the computations. A steady mixing-plane method is used on the impeller/volute interface for simulating the unsteady interaction phenomena. The axial thrust is predicted from the turbopump calculation in its entirety, which is necessary for such estimation. Moreover, the effects of each component on the pump performance are investigated at a design condition through the analysis of flow structures. The predicted performance is in good agreement with experimental data in terms of head rise, efficiency and volute wall pressure distributions despite of highly complex flow structures being present. The computational results also show that the axial and radial thrusts are within the design limit although corresponding experimental measurements were not taken.